One thing not brought out in discussions is the effect slightly misaligned bearing bores in the two bearing quill has on the drive sleeve(that plastic do-hickey). Single bearing play actually provides 'automatic' alignment end to end. The plastic do-hicky functions similar to a second bearing.

I think a flexible joint behind the inner bearing would be better, but likely more $$$ if even possible.

True, the two bearing quill with two piece shaft. I'm not too concerned about my 10er two bearing quills.